1. Field of the Invention
This invention relates to integrated circuits, and more particularly, to multiplexing and level shifting circuits.
2. Description of the Related Art
Many integrated circuits (ICs) often times incorporate multiple functions onto a single die. For example, a system on a chip (SOC) may incorporate multiple processor cores, one or more memory types, input/output (I/O) units, and graphics units, among other functional units. Due to the large number of signals that may be transferred between such units. In some cases, a given unit may select among signals transferred from one or more other units using multiplexers.
In addition to the large numbers of signals being transferred between the various units of an IC, many functional units operate in different voltage domains. For example, a processor core may operate at a first voltage in a first voltage domain, a memory may operate at a second voltage in a second voltage domain, and so on. Since different functional unit in different voltage domains may need to communicate with one another, level shifting circuits may be utilized in the transfer of signals from one voltage domain to the next.